Optical unit and image display device thereof

ABSTRACT

A single plate type optical unit and display device to utilize light with high efficiency in a simple method is configured so a dichroic mirror separates light into a plurality of colors, and the plurality of colors of light reflected by the dichroic mirror are beamed onto a rotating multisurface element, the plurality of colors of light emitted from the rotating multisurface element are each beamed onto different locations on the display element, and by rotating the rotating multisurface element, the plurality of colors of light are moved in one direction along the display element, and a color image is beamed from a projection lens.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to projection devices such asliquid crystal projectors, projection image display devices and opticalengines such as reflective image display projectors and beam type rearprojection television for projecting images on a screen using lightvalve devices such as liquid crystal panels or image display elements,and relates in particular to technology for beaming a plurality of lightcolors onto different light valve element locations using a rotatingmultisurface element, and changing the beaming locations in sequence.

[0003] 2. Description of the Related Art

[0004] An optical unit is known in the related art for passing lightfrom a light source through a first and a second array lens, a polarizedbeam splitter (PBS) and a collimator lens, and then separating the lightinto red light, blue light and green light by using a plurality ofdichroic mirrors, and then changing the optical paths of each separated(colored) light by means of respective rotating prisms and beaming eachlight onto respectively different locations on a light valve element(hereafter simply referred to as a display element or image displayelement) and also scroll each light beam in sequence in a fixeddirection on the display element locations.

SUMMARY OF THE INVENTION

[0005] The above described optical unit of the related art possessed theadvantage that assembly of the single plate utilized by the displayelement was simple. However the optical unit had to be made large insize since a plurality of prisms were required. Further, besides havinga high price due to use of a plurality of rotating prisms, a largenumber of lenses and many dichroic mirrors, the lightutilizationefficiency was poor because of the many lenses that were used. Also, therotation phase of a plurality of rotating prisms had to be aligned inorder to adjust the display element positions upon which the red, greenand blue light were beamed and this alignment was difficult.Furthermore, noise prevention methods were needed due to the pluralityof motors being used.

[0006] The present invention therefore has the object of providing acompact and low-priced optical unit.

[0007] Another object of the present invention is to provide novel andeffective image display technology, allow simple position alignment fora plurality of light beamed onto a display element, and provide goodlight utilization efficiency.

[0008] To achieve the above objects of the invention, the optical unitis comprised of a light source, a display element to form an opticalimage according to an image signal from the light emitted from the lightsource, a light color separator means for separating the light emittedfrom the light source into a plurality of light colors, a rotatingmultisurface element input with a plurality of light colors emitted bythe light color separator means for changing the optical path andbeaming the plurality of light colors onto different locations on thedisplay element while scrolling the light beam in one direction, and aprojection device to light emitted from the display element as a colorimage.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is structural views showing the first embodiment of theoptical unit of the invention.

[0010]FIG. 2 is perspective views of the display element for describingthe status of the beam of three-colored light on the display element.

[0011]FIG. 3 is structural views showing the second embodiment of theoptical unit of the invention and a flat view of the display element.

[0012]FIG. 4 is structural views showing the second embodiment of theoptical unit of the invention and a flat view of the display element.

[0013]FIG. 5 is structural views showing the second embodiment of theoptical unit of the invention and a flat view of the display element.

[0014]FIG. 6 is a structural view showing the first embodiment of thedisplay device of the present invention.

[0015]FIG. 7 is structural views showing the third embodiment of theoptical unit of the present invention.

[0016]FIG. 8 is structural views showing the fourth embodiment of theoptical unit of the present invention.

[0017]FIG. 9 is structural views showing the fifth embodiment of theoptical unit of the present invention.

[0018]FIG. 10 is structural views showing the sixth embodiment of theoptical unit of the present invention and a flat view of the displayelement.

[0019]FIG. 11 is structural views showing the sixth embodiment of theoptical unit of the present invention and a flat view of the displayelement.

[0020]FIG. 12 is structural views showing the sixth embodiment of theoptical unit of the present invention and a flat view of the displayelement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The embodiments of the present invention are hereafter describedwhile referring to the work drawings.

[0022]FIG. 1 is structural views showing the first embodiment of theoptical unit of the invention.

[0023] In this figure, the light emitted from the light source 1obtained after reflection from a reflector is input to a first arraylens 2 for forming a plurality of secondary light source images, andthen passed through a second array lens 3 formed by a plurality offocusing lenses and installed in the vicinity of the second light sourceimage, for forming lens images for each of the first array lenses 2 inthe liquid crystal display element 12. The mixed light of P polarizedlight and S polarized light that passed through the second array lens 3,the S polarized light for example is aligned by the polarized beamsplitter 4 (hereafter referred to simply as PBS) and the λ/2 wavelengthplate 4 a, and passed through the first collimator lens 5 a and secondcollimator lens 5 b and the light respectively reflected as red light,green light and blue light by the red dichroic mirror 7 a for reflectingred light, the green dichroic mirror 6 b for reflecting green light, andthe B dichroic mirror or reflecting mirror 7 c (hereafter referred to asdichroic mirror group) for reflecting B light. The red light, greenlight and blue light respectively pass through the third collimator lens5 c, and irradiate different locations on the respective reflectingrotating polygonal mirrors 43, and are reflected from the reflectingrotating polygonal mirrors 43. In this embodiment, the reflectingrotating polygonal mirrors 43 has eight surfaces however there is norestriction on the number of surfaces. The dichroic mirror group 7 a, 7b, and 7 c in this embodiment is the three colors red, blue and green.However a combination of red, green blue and white, or yellow, cyan,magenta, or a combination of yellow, cyan, magenta or a combination ofred, yellow, green cyan and magenta, or red and orange, or green, blueand violet may be used. In such cases, the dichroic mirror groupconstituting the color separator means may consist of a plurality ofplates such as three or more plates. In this case, the scroll zone onthe display element may be three or more types.

[0024] In the case of two-plate type optical unit (each plate installedrespectively on one of the two surfaces of a cube type PBS utilizing 2display elements), a structure may be used where only the scrollinglight arrives on the first display element via the rotating polygonmirror, and the remaining non-scrolling light is made to arrive directlyon the second display element by way of a fixed mirror and a lens.

[0025] When the red light, green light and blue light are reflected fromone surface of the reflecting rotating multisurface element 43, theirrespective optical paths intersect. When any of the red light, greenlight, and blue light are reflects as two lights from one surface of thereflecting rotating multisurface element 43, then the optical paths oftheir light intersect (related later on while referring to FIG. 4, FIG.5). The red light, green light and blue light emitted from thereflecting rotating multisurface element 43 pass through the converginglens 6, the condensing lens 8, and the polarizing plate 9 a and afterreflecting from the PBS 10, pass through the λ/4 wavelength plate 11 andare beamed on different locations on the display element 12. P polarizedlight converted from the S polarized light emitted from the displayelement 12 passes through the PBS10, and after further permeatingthrough the polarizing plate 9 b, is displayed as an enlarged image onthe screen (not shown in drawing) by way of the projection lens 13.

[0026] Any of a transmissible liquid crystal device, a reflecting liquidcrystal display element, a ferroelectric liquid crystal device as wellas a micro-mirror image display element may serve as needed, as thedisplay element of the present invention. In the present embodiment, thereflecting liquid crystal display element or the ferroelectric liquidcrystal device can be used as the display element 12.

[0027] In the embodiment of FIG. 1, the optical paths of the red light,green light and blue light reflected by the dichroic mirror group 7 a, 7b, 7 c are aligned so that the red light, green light and blue light arebeamed onto the specified locations on the display element 12. Also, thesize and number of rotating polygonal mirrors is determined so that whenthe rotating multisurface element 43 has rotated these optical paths,the red light, green light and blue light can be moved at approximatelythe same speed in one direction.

[0028] Further, a combination of dichroic prisms and reflecting mirrorscan be used instead of the dichroic mirror group 7 a, 7 b, 7 c, toseparate the red light, green light and blue light and control theoptical axis with reflecting mirror.

[0029] The light beam (irradiation) status of the red light, green lightand blue light at the time of reflection from the reflecting rotatingmultisurface element 43 onto the display element 12 is next describedwhile referring to FIG. 2.

[0030]FIG. 2 is an oblique view of the display element for describingthe beaming of the three color light on the display element. In FIG. 2,12R is the location where the red light is beamed upon, 12G is thelocation where the green light is beamed, and 12B shows the locationwhere the blue light is beamed. The blue light, green light and redlight are beamed upon the display element 12 simultaneously. Here, 21R,21G and 21B are respectively the locations where the red light, greenlight and blue light are next beamed, and the address for beaming thered light, green light and blue light is performed. The size of thatlocation is determined by the write time of the display element 12,namely, the response time of the display element 12 and the scroll speedso that even one line is sufficient when the response time issufficiently faster than the movement time for scrolling one line. Whenthe response time is slow, a number of lines is assigned to match thatresponse time.

[0031] When first beaming these lights from above by scrolling along thedisplay element 12, each color is written in sequence from above, asinformation matching each color in the respective address in locations12R, 12G and 12B, and the red light, green light, blue light is thenbeamed in sequence from above on each color area on the display element12. During that time, addresses are written in the locations 21R, 21Gand 21B. When the address writing in the locations 21R, 21G and 21B iscomplete, the red light, green light, blue light beaming on therespective locations 12R, 12G and 12B moves downward along the displayelement 12 just by an amount corresponding to the locations 21R, 21G and21B, and red light, green light, blue light beams (irradiates) on thelocations 21R, 21G and 21B. When writing in the locations 21R, 21G and21B is complete, address writing is then performed on the lower line.The locations irradiated by the red light, green light and blue light inthis way move downward in sequence.

[0032] The size of the locations 12R, 12B and 12B are approximately thesame in this embodiment, so the lens shapes of the first array lens 2are formed to resemble the light band shape of the red, green or bluelight beaming on the locations 12R, 12G and 12B on the display element12.

[0033] The second embodiment of the present invention is next describedwhile referring to FIG. 3 through FIG. 5.

[0034]FIG. 3, FIG. 4 and FIG. 5 are structural views showing the secondembodiment of the optical unit of the invention and flat views of thedisplay element. FIG. 3A, FIG. 4A and FIG. 5A are structural views ofthe respective optical units. FIG. 3B, FIG. 4B and FIG. 5B are showlocations on the display element irradiated by the red light, greenlight and blue light. In the figure, when the reflecting rotatingmultisurface element 43 is rotating in the direction of arrow A. FIG. 3Ashows the embodiment when the red light, green light and blue lightreflected by the dichroic mirror groups 7 a, 7 b, 7 c is beamed upon onesurface of the reflecting rotating multisurface element 43. In thiscase, as shown in FIG. 3B, the locations irradiated by the red light,green light and blue light, are 12R, 12G and 12B in sequence from leftto right on the display element 12. The embodiment in FIG. 4A shows thecase when the red light and green light reflected by the dichroic mirrorgroups 7 a, 7 b, 7 c from among the red, blue and green light, arebeamed upon one surface, and the blue light is beamed upon the nextsurface. In this case, as shown in FIG. 4B, the locations beamed upon bythe red light, green light and blue light, are 12B, 12R and 12G insequence, from the right, on the display element 12.

[0035] In the embodiment shown in FIG. 5A, only the red light from amongthe light reflected by the dichroic mirror groups 7 a, 7 b, 7 c isbeamed upon the surface, and the green light and blue light is beamedupon the next surface. In this case, as shown in FIG. 5B, the locationson which the red light, green light and blue light is beamed, are thelocations 12G, 12B and 12R in sequence from the right on the displayelement 12.

[0036] Sections in FIG. 3 through FIG. 5 assigned with the samereference numerals are identical to the same sections in FIG. 1 so anexplanation is omitted here. In FIG. 3 through FIG. 5, the pointdiffering from FIG. 1 is that, the λ/2 wavelength plate 4 a, and thesecond collimator lens 5 b are omitted on the optical path from thelight source 1 to the dichroic mirror group 7 a, 7 b, and 7 c. The thirdcollimator lens 5 c is eliminated from the optical path from thedichroic mirror group 7 a, 7 b, and 7 c to the reflecting rotatingmultisurface element 43 and a convergence lens 6 a is used instead. Theoptical path has the same structure from the reflecting rotatingmultisurface element 43 to the projection lens 13. This embodimentoperates the same as the embodiment of FIG. 1, and along with red light,green light and blue light beaming onto the respective locations 12 a,12 b and 12 c on the display element 12, those locations are moved insequence in one direction on the display element 12, and a color imagecan be displayed on a screen (not shown in drawing) on one displayelement 12.

[0037]FIG. 3 shows the case when the red light, green light and bluelight reflected by the dichroic mirror group 7 a, 7 b, and 7 c arerespectively converged on one surface of the reflecting rotatingmultisurface element 43. In this case, the optical axes of the redlight, green light and blue light reflected from the reflecting rotatingmultisurface element 43 intersect between the light beam input surfaceof the PBS10 and the reflecting rotating multisurface element 43. Theexample in this embodiment described an eight surface element but thereis no restriction on the number of surfaces.

[0038] When red light and green light are beamed upon one surface of thereflecting rotating multisurface element 43, and blue light is beamed onthe next surface as shown in FIG. 4, the green light and red light arethen beamed on the PBS10, after the optical axes of the green light andthe red light reflected from the reflecting rotating multisurfaceelement 43 intersect each other, however the optical axis of the bluelight does not intersect with the axes of the red light and green lightand is input to the PBS10.

[0039] When the red light is beamed upon one surface of the reflectingrotating multisurface element 43, and the green light and blue light arebeamed on the next surface as shown in FIG. 5, the light is beamed ontothe input surface of the PBS10 after the optical axes of the green lightand blue light reflected from the next surface of the reflectingrotating multisurface element 43 have intersected each other.

[0040] It can be seen from the above description that when a pluralityof light colors are beamed upon one surface of the reflecting rotatingmultisurface element 43, the light is beamed into the PBS10 after theoptical axes of the plurality of light reflected from the reflectingrotating multisurface element 43 intersect.

[0041] The embodiment of the display device of the present invention isdescribed next.

[0042]FIG. 6 is a structural view showing the first embodiment of thedisplay device of the present invention.

[0043] Sections in FIG. 1, and FIG. 3 through FIG. 5 assigned with thesame reference numerals are identical to the same sections in thisfigure so an explanation is omitted here. In this embodiment, theoptical path from the light source 1 to the dichroic mirror group 7 a, 7b, and 7 c is the same as the embodiment of FIG. 1, and the optical pathfrom the dichroic mirror group 7 a, 7 b, and 7 c to the projection lens13 is the same as the optical path in FIG. 3 through FIG. 5. Theoperation of the optical unit of this embodiment is also the same as inFIG. 1 and FIG. 3 through FIG. 5 so that a color image can be shown onthe screen (not shown in drawing) by the beaming of light from theprojection lens 13.

[0044] In the embodiment of FIG. 6, the reference numeral 24 denotes apower supply, the reference numeral 25 denotes an image display circuitfor processing image signals and the reference numeral 26 denotes anexhaust fan, and the image display device is comprised by mounting thesecomponents in an optical unit having an optical path from the lightsource 1 to the projection lens 13.

[0045] The embodiment when the direction from the light source 1 to thedichroic mirror group 7 a, 7 b, and 7 c is the same as the directionfrom the reflecting rotating multisurface element 43 to the projectionlens 13 is described next while referring to FIG. 7.

[0046]FIG. 7 is structural views showing the third embodiment of theoptical unit of the present invention. Sections in the figure assignedwith the same reference numerals are identical to the same sections inthe embodiments of FIG. 1 and FIG. 3 through FIG. 5 so an explanation isomitted here.

[0047] The optical path between the light source 1 to the dichroicmirror group 7 a, 7 b, 7 c is different from the optical path shown inFIG. 1 in that there is no second collimator 5 b however the othercomponents of the optical path are the same.

[0048] In the optical path from the dichroic mirror group 7 a, 7 b, and7 c to the reflecting rotating multisurface element 43 is different fromthe optical path shown in FIG. 1 in that there is no third collimator 5c, however this collimator 5 c may also be used. Two types of converginglenses 6 a, 6 b are used in the optical path from the reflectingrotating multisurface element 43 to the PBS10. The structure from thePBS10 onwards is the same as shown in FIG. 1. The dotted line in FIG. 7indicates the green light, while the dot-dash line indicates the opticalaxis of the green light. The optical axes of the red light and bluelight are omitted but their optical axes can be shown as in FIG. 1.

[0049] In this embodiment, among the three (colors of) lights reflectedfrom the dichroic mirror group 7 a, 7 b, and 7 c, the light in thecenter, or in other words the green light is focused and converged onone surface of the reflecting rotating multisurface element 43. In thiscase, the red light and the blue light are beamed centered around thegreen light on the reflecting rotating multisurface element 43 so thateach surface of the reflecting rotating multisurface element 43 can bemade smaller compared to when the green light is converged onto otherthan the center of the reflecting rotating multisurface element 43.

[0050] Also in the present embodiment, the red light, green light andblue projected light can be emitted from the projection lens 13 on anoptical axis approximately in parallel with the optical axis of thedichroic mirror group 7 a, 7 b, and 7 c from the light source 1.

[0051] There is no restriction here on the collimator lens and these maybe installed behind the dichroic mirror group 7 a, 7 b, and 7 c. Theparticular features of the dichroic mirror group 7 a, 7 b, and 7 c mayalso be interchanged such as by either of the combinations of RGB, BGRhowever, weak light wavelengths should have priority according to theoutput of the light source serving as the light source, in other words,the initial reflection method is satisfactory for reducing the permeance(transmittance) count.

[0052] The fourth embodiment of the present invention is described nextwhile referring to FIG. 8.

[0053]FIG. 8 is a structural view showing the fourth embodiment of theoptical unit of the present invention. In this figure, after the lightfrom the light source 1 has passed through the first collimator lens 5 aand the second collimator lens 5 b, the light is input to the firstlight valve 46. The polarization direction of the light is aligned bythe PBS45 a, PBS or the full reflecting prism or the full reflectingmirror 45 b, or the λ/2 wavelength plate 4 b while reflecting from theinternal surface of the first light valve 46 and advancing, and is inputfor example as S polarized light to the second light valve 44. The Spolarized light input to the second light valve 44 advances whilereflecting from the internal surfaces of the second light valve 44 andthe red light, green light and blue light are respectively reflectedfrom the dichroic mirror group 7 a, 7 b, and 7 c and are input to thereflecting rotating multisurface element 43. The red light, green lightand blue light reflected from the reflecting rotating multisurfaceelement 43 pass through the first converging lens 6 a, second converginglens 6 b, third convergence lens 6 c and polarizing plate 9 a and areinput to the PBS10. The optical path from there onwards is the same asin the case of FIG. 1.

[0054] A color image can also be displayed on the screen in thisembodiment. Also in this embodiment, light projected from the projectionlens 13 can be emitted on an optical path in a direction perpendicularto the optical axis of light from the dichroic mirror group 7 a, 7 b,and 7 c and light source 1.

[0055] In this embodiment, the light is formed into S polarized light bymeans of the PBS45 a and the fully reflecting prism 45 b so that a lineor streak can be obtained between the S polarized light emitted from Spolarized light emitted from the PBS 45A and the S polarized lightemitted from the fully reflecting prism 45 b. When these two S polarizedlights pass through the second light valve 44, the line or streakoccurring among the two S polarized lights is eliminated by reflectionof the two S polarized lights internally in the second light valve 44.If not concerned with the line or streak occurring among the two Spolarized lights, then the second light valve 44 for aligning the Spolarized light may be omitted.

[0056] Insertion of the PBS45 a causes the width of the light of thelight valve 46 to enlarge in one direction to approximately twice theoriginal size so the shape of the output beam opening of the light valve44 can easily be made to a similar shape (band rectangular shape) as thescroll band shape on the display element. Also the input opening shapeof the light valve 46 can be designed to a shape (for example, anapproximately square shape) to match the light spot shape, so that lightloss can be limited and the light can easily be extended to arectangular shape and extremely good efficiency obtained. The outputlight beam opening of the light valve 44 can also be made to reconvergelight onto the display element without having to form a rectangularaperture so that there is no need to cutoff the light such as by using arectangular aperture and the efficiency is good.

[0057] When a micromirror type image display element is utilized as thedisplay element 12 in this embodiment, there is no need to align thedirection of the polarized light so that the PBS45 a, the fullyreflecting prism or the fully reflecting mirror 45 b, and the λ/2wavelength plate 4 b are not needed.

[0058] The fifth embodiment of the optical unit of the present inventionis described next.

[0059]FIG. 9 is structural views showing the fifth embodiment of theoptical unit of the present invention. In the figure, the dotted lineindicates only the green light and the dot-dashed line indicates thegreen light optical axis. The optical axes of the other colors of lightare the same as for example in FIG. 1. Sections in the figure having thesame reference numbers as in FIG. 1 have the element functions so adescription is omitted.

[0060] In this embodiment, the light from the light source 1 is input toa first array lens 2 for forming a plurality of secondary light sourceimages, and passed through a second array lens 3 formed by a pluralityof focusing lenses installed in the vicinity where the plurality ofsecondary light source images are formed, and that converges each of thelens images of the first array lens 2 onto the liquid crystal displayelement 12. The mixed light of P polarized light and S polarized lightthat passed the second array lens 3 is aligned into S polarized light bythe polarized beam splitter 4, and by means of the first collimator lens5 a, the red light, green light and blue light are respectivelyreflected by the red dichroic mirror 7 a for reflecting red light, thegreen dichroic mirror 7 b for reflecting green light, and blue dichroicmirror or reflecting mirror 7 c for reflecting blue light (Anultraviolet permeable mirror may be used, and if the structure reflectsthe red light last, then may comprise an IR permeable mirror.). The redlight, green light and blue light irradiate onto respectively differentlocations on the reflecting rotating multisurface element 43 and arereflected by the reflecting rotating multisurface element 43. After thered light, blue light and green light reflecting from the reflectingrotating multisurface element 43 have passed through the secondcollimator lens 5 b, and been reflected by the reflecting mirror 16, theoptical path is changed approximately 90 degrees and passes through thecondenser lens 8. The red light, blue light and green light that passedthrough the condenser lens 8, passed through the first polarizing plate9 a, is reflected by the PBS10, passes through the λ/4 wavelength plate11 and is input to the reflecting type display element 12. The redlight, blue light and green light converted into P polarized light atthe display element 12, passes this time through the PBS10, and isoutput by the second polarizing plate 9 b. The optical axis emitted fromPBS10 is parallel to the direction of the light from the light source 1and is output facing opposite the light from the light source 1.

[0061] In this embodiment, an optical unit can be configured withoutusing a convergence optical system.

[0062] An example is next described using a transmissible rotatingpolygonal mirror in the optical unit.

[0063]FIG. 10, FIG. 11 and FIG. 12 are structural views showing thesixth embodiment of the optical unit of the present invention and flatviews of the display element. FIG. 10A, FIG. 11A and FIG. 12A arestructural drawings of the respective optical units. FIG. 10B, FIG. 11Band FIG. 12B show locations on the display element irradiated by the redlight, green light and blue light.

[0064]FIG. 10A shows the-case when the red light, green light and bluelight irradiate (beam) onto one surface of the transmissible rotatingpolygonal mirror with optical paths of mutually different directions,and the red light, green light and blue light are emitted from a surfacefacing that one surface. The red light, green light and blue lightirradiate (beam) respectively in sequence from the top, onto thelocations 12R, 12G and 12B on the surface of the display element 12 asshown in FIG. 10B. The embodiment in FIG. 11, shows the case when thered light, green light and blue light irradiate (beam) onto two surfacesof the transmissible rotating polygonal mirror 43 from optical axes ofmutually different directions, and the red light, green light and bluelight are emitted from surfaces opposing (facing) those two surfaces. Asshown in FIG. 11B, the red light, green light and blue light isirradiated onto the locations 12G, 12B and 12R in sequence from above,on the surface of the display element 12. The embodiment in FIG. 12Ashows the case when the red light, green light and blue light irradiate(beam) onto two surfaces of the transmissible rotating polygonal mirror43 from optical axes of mutually different directions, and the redlight, green light and blue light are emitted from surfaces opposing(facing) those two surfaces, and as shown in FIG. 12B, the red light,green light and blue light irradiate (beam) in sequence from above, ontothe locations 12B, 12R and 12G on the display element 12.

[0065] In FIG. 10 through FIG. 12, the light from the light source 1passes through the first array lens 2 and the second array lens 3, andthe polarity of the light is aligned by the PBS4, and passes through thecollimator lens 5 for example as S polarized light, and the red light,green light and blue light are respectively reflected by the reddichroic mirror 7 a for reflecting red light, the green dichroic mirror7 b for reflecting green light, and a blue dichroic mirror or reflectingmirror 7 c for reflecting blue light. The red light, green light andblue light reflected by the dichroic mirror group 7 a, 7 b, 7 c pass thetransmissible rotating polygonal mirror 47. The red light, green lightand blue light permeating through the transmissible rotating polygonalmirror 47, then passes through the condenser lens 8 and the firstpolarizing plate 9 a, is reflected by the λ/4 wavelength plate 11 and isinput to the reflecting type display element 12.

[0066] The red light, green light and blue light reflected at thisdisplay element 12 and polarized into P polarized light, passes thePBS10 and is input to the projection lens 13. In this embodiment, thedirection of the light emitted from the projection lens 13 isapproximately parallel with the direction of light emitted from thelight source 1, and faces the opposite direction.

[0067] In the embodiments in FIG. 10 through FIG. 12, the transmissiblerotating polygonal mirror 47 rotates clockwise (direction of arrow A) asseen in the drawing.

[0068] In FIG. 10, the red light, green light and blue light reflectedby the dichroic mirror group 7 a, 7 b, 7 c on mutually different opticalaxes, are input to one surface of the transmissible rotating polygonalmirror 47, pass through the transmissible rotating polygonal mirror 47,and after being emitted from a surface facing the transmissible rotatingpolygonal mirror 47, these optical axes intersect and are input to thecondenser lens 8.

[0069] In FIG. 11, the transmissible rotating polygonal mirror 47 isrotated clockwise in the case of FIG. 10, and the red light input to onesurface, and the green light and blue light input to the next surface,and the respective red light, green light and blue light pass thetransmissible rotating polygonal mirror 47, the red light is emittedfrom a surface different from the surface facing the one surface (of themultisurface element 47), the green light is input from the nextsurface, and emitted from a surface facing that surface, the blue lightis input from the next surface, and emitted from a surface differentfrom the surface facing that one surface. In this embodiment, the greenlight and blue light input from different surfaces, are emitted fromdifferent surfaces and after intersecting, are input to the PBS10.

[0070] In FIG. 12, the red light is input to one surface of thetransmissible rotating polygonal mirror 47, and the green light and bluelight input from the next surface, and the red light, green light andblue light respectively pass the transmissible rotating polygonal mirror47. The red light is output from the surface facing the next surface,the green light is output from the surface facing the one surface, andthe blue light is output from the surface facing the next surface. Afterthe red light and blue light output from the surface facing the nextsurface have intersected, they pass the condenser lens and are input tothe PBS10.

[0071] In the embodiments from FIG. 10 through FIG. 12, at least two ofthe red light, green light and blue light intersect after being outputfrom the transmissible rotating polygonal mirror 47.

[0072] In this embodiment, any material capable of permeating light canbe used as the material for the transmissible rotating polygonal mirror47. Also, the number of surfaces of the transmissible rotating polygonalmirror 47 is not limited to eight surfaces and any polyangular shape canbe utilized if having three or more sides. There are further norestrictions on the size of the transmissible rotating polygonal mirror47.

[0073] The invention as described above can irradiate a respectiveplurality of colors on different locations on one display element byutilizing a dichroic mirror group to separate and reflect light into aplurality of colors, and a rotating multisurface element to change thedirection of this plurality of colors;

[0074] furthermore, the locations irradiated (or beamed upon) on thedisplay element by the plurality of colors can be sequentially changedin one direction by rotating the rotating multisurface element, so thata color image can be obtained using one display element that further hasa simple structure.

[0075] Also in this invention, the light from the light source isseparated into a plurality of colors and this separated plurality oflight colors can be irradiated with good efficiency upon a displayelement so that the utilization efficiency of the light is good.

[0076] In this invention, only one rotating multisurface element is usedso that the positioning of the plurality of light colors irradiated uponthe display element is simple.

[0077] In this invention therefore, as described above, an optical unithaving a simple single plate type structure can be obtained.

[0078] An optical unit having good light utilization efficiency can beobtained. Further, an optical unit having good simple positioning of theplurality of colors on the display element can also be obtained.

What is claimed is:
 1. An optical unit comprising a light source, animage display element to form an optical image according to an imagesignal output from the light emitted from said light source, a colorseparator means for separating the light emitted from said light sourceinto a plurality of light colors, a rotating multisurface element inputwith a plurality of light colors emitted by said color separator meansfor changing the respective optical axis direction and beaming saidplurality of light colors onto different locations on said displayelement while scrolling the light beam in one direction, and aprojection device for projecting light emitted from said image displayelement as a color image.
 2. An optical unit according to claim 1,wherein said color separator means is comprised of a dichroic mirror ora dichroic prism and reflecting mirror.
 3. An optical unit according toclaim 1, wherein of said plurality of light colors emitted from saidrotating multisurface element, two of said light colors are input tosaid image display element after the optical paths of said two lightcolors intersect.
 4. An optical unit according to claim 1, wherein saidrotating multisurface element is a reflecting rotating multisurfaceelement, a plurality of said light colors irradiate upon the surface ofsaid reflecting rotating multisurface element, and the reflected lightfrom said reflecting rotating multisurface element irradiates onto saidimage display element.
 5. An optical unit according to claim 1, whereinsaid rotating multisurface element is a permeating rotating multisurfaceelement, a plurality of said light colors irradiate upon the surface ofsaid permeating rotating multisurface element, and the light irradiatesonto said image display element by permeating through said permeatingrotating multisurface element.
 6. An optical unit according to claim 1,wherein a convergence optical system is installed on the optical pathdownstream of said rotating multisurface element, and an approximatelyrectangular light image is converged onto said image display element. 7.An optical unit according to claim 1, wherein after the light from thelight source passes through an integrator element, said light irradiatessaid color separator means, and among the plurality of said light colorsirradiated onto said image display element, at least one light shaperesembles the output beam opening of said integrator element or theshape of the lens cells.
 8. An optical unit according to claim 1,wherein said unit utilizes a micromirror image display element.
 9. Anoptical unit according to claim 1, wherein a polarized beam splitter isformed for aligning the polarizing direction of the light emitted fromsaid light source, and the plurality of light colors aligned by saidpolarized beam splitter are irradiated upon an image display elementcomprised of any of a transmissible liquid crystal device, a reflectingliquid crystal display element, or a ferroelectric liquid crystaldevice.
 10. An optical unit comprising a light source, an image displayelement for forming an optical image according to an image signal outputfrom the light emitted from said light source, a first array lens forforming a plurality of secondary light source images from said lightsource, a second array lens for converging each of the lens images ofsaid first array lens, a polarized beam splitter to align the polarizingdirection of the light, a first dichroic mirror to isolate a first colorlight from light inside said polarized beam splitter and control theoptical axis direction of said first color light, a second dichroicmirror to isolate a second color light from among light inside saidpolarized beam splitter and control the optical axis direction of saidsecond color light, a third dichroic mirror or reflecting mirror tocontrol the optical axis direction of a third color light from amonglight inside said polarized beam splitter, a reflecting rotatingmultisurface element to controllably reflect the optical axis directionof each of said first, said second and said third color light beamedfrom said first dichroic mirror, said second dichroic mirror, said thirddichroic mirror or reflecting mirror, and along with beaming said first,said second and said third color light onto different locations on saidimage display element, to scroll in one direction along the locationsbeamed upon by first, said second and said third color light, and aprojection device to project light emitted from said image displayelement as a color image.
 11. An optical unit according to claim 10,wherein at least two light colors from among said first, said second andsaid third color lights reflected from the surface of said reflectingrotating multisurface element are beamed onto said image display elementafter intersecting.
 12. An optical unit according to claim 10, whereinthe shape of each lens cell of said first array lens and said secondarray lens resemble the shape of said first, said second, and said thirdcolor light beamed on said image display element.
 13. An optical unitaccording to claim 10, wherein of said first, said second, and saidthird color light emitted from said first, said second dichroic mirror,said third dichroic mirror or reflecting mirror, at least a color lightis converged onto the input surface of said reflecting rotatingmultisurface element by a convergence means.
 14. An optical unitaccording to claim 10, wherein the light converged onto the inputsurface of said reflecting rotating multisurface element is made toreconverge on said image display element.
 15. An optical unit comprisinga light source, an image display element for forming an optical imageaccording to an image signal output from the light emitted from saidlight source, a light pipe for permeating light while reflecting lightfrom said light source, a first dichroic mirror to isolate a first colorlight from among light inside said light pipe and control the opticalaxis direction of said first color light, a second dichroic mirror toisolate a second color light from among light inside said light pipe andcontrol the optical axis direction of said second color light, a thirddichroic mirror to isolate a third color light from among light insidesaid light pipe and control the optical axis direction of said thirdcolor light, a reflecting rotating multisurface element to controllablyreflect the optical axis direction of each of said first, said secondand said third color light beamed from said first dichroic mirror, saidsecond dichroic mirror, said third dichroic mirror or reflecting mirror,and along with beaming said first, said second and said third colorlight onto different locations on said image display element, to scrollin one direction along the locations beamed upon by first, said secondand said third color light, and a projection device to project lightemitted from said image display element as a color image.
 16. An opticalunit according to claim 15, wherein a polarized beam splitter foraligning the polarizing direction of light from said optical pipe isinstalled downstream of said light pipe.
 17. An optical unit accordingto claim 16, wherein other light pipes are installed downstream of saidpolarized beam splitter.
 18. An optical unit comprising a light source,an image display element for forming an optical image according to animage signal output from the light emitted from said light source, afirst array lens for forming a plurality of secondary light sourceimages from said light source, a second array lens for converging eachof the lens images of said first array lens, a polarized beam splitterto align the polarizing direction of the light, a first dichroic mirrorto isolate a first color light from light inside said polarized beamsplitter and control the optical axis direction of said first colorlight, a second dichroic mirror to isolate a second color light fromamong light inside said polarized beam splitter and control the opticalaxis direction of said second color light, a third dichroic mirror orreflecting mirror to control the optical axis direction of a third colorlight from among light inside said polarized beam splitter, a permeatingrotating multisurface element to controllably pass light of the opticalaxis direction of each of said first, said second and said third colorlight beamed from said first dichroic mirror, said second dichroicmirror, said third dichroic mirror, and along with beaming said first,said second and said third color light onto different locations on saidimage display element, to scroll the locations beamed upon by first,said second and said third color light in one direction, and aprojection device to project light emitted from said image displayelement as a color image.
 19. An optical unit according to claim 18,wherein at least two color lights from among said first, said second andsaid third color lights reflected from the surface of said permeatingrotating multisurface element are beamed onto said image display elementafter intersecting.
 20. An optical unit comprising a light source, animage display element to form an optical image according to an imagesignal output from the light emitted from said light source, a colorseparator means for separating the light emitted from the light sourceinto a plurality of light colors, a rotating multisurface element inputwith a plurality of light colors emitted by said color separator meansfor changing the optical path and beaming the plurality of light colorsonto different locations on said display element while scrolling thelight beam in one direction, and a projection device to project lightemitted from said image display element as a color image; wherein saidcolor separator means is comprised of a dichroic mirror or a dichroicprism and reflecting mirror; of said plurality of light colors emittedfrom said rotating multisurface element, two of said light colors areinput to said image display element after the optical paths of said twolight colors intersect; said rotating multisurface element is areflecting rotating multisurface element, a plurality of said lightcolors irradiate upon the surface of said reflecting rotatingmultisurface element, and the reflected light from said reflectingrotating multisurface element irradiates onto said image display elementand; after the light from the light source passes through an integratorelement, said light irradiates said color separator means, and among theplurality of said light colors irradiated onto said image displayelement, at least one light shape resembles the output beam opening ofsaid integrator element or the shape of the lens cells and, aconvergence optical system is installed on the optical path downstreamof said rotating multisurface element, and a rectangular light imagewith a shape similar to the shape of each cell in said image displayelement is converged onto said image display element
 21. An imagedisplay device comprising: an optical unit having a light source, animage display element to form an optical image according to an imagesignal output from the light emitted from said light source, a colorseparator means for separating the light emitted from said light sourceinto a plurality of light colors, a rotating multisurface element inputwith a plurality of light colors emitted by said color separator meansand changing the respective optical axis direction and beaming saidplurality of light colors onto different locations on said displayelement while scrolling the light beam in one direction, and aprojection device to project light emitted from said image displayelement as a color image; an image processor circuit; and a powersupply.
 22. An image display device comprising: an optical unit having alight source, an image display element for forming an optical imageaccording to an image signal output from the light emitted from saidlight source, a first array lens for forming a plurality of secondarylight source images from said light source, a second array lens forconverging each of the lens images of said first array lens, a polarizedbeam splitter to align the polarizing direction of the light, a firstdichroic mirror to isolate a first color light from light inside saidpolarized beam splitter and control the optical axis direction of saidfirst color light, a second dichroic mirror to isolate a second colorlight from among light inside said polarized beam splitter and controlthe optical axis direction of said second color light, a third dichroicmirror or reflecting mirror to control the optical axis direction of athird color light from among light inside said polarized beam splitter,a reflecting rotating multisurface element to controllably reflect theoptical axis direction of each of said first, said second and said thirdcolor light beamed from said first dichroic mirror, said second dichroicmirror, said third dichroic mirror or reflecting mirror, and along withbeaming said first, said second and said third color light ontodifferent locations on said image display element, to scroll in onedirection along the locations beamed upon by first, said second and saidthird color light, and a projection device to project light emitted fromsaid image display element as a color image; an image processor circuit;and a power supply.